On July 27, researchers announced the progression-free survival (PFS) results for the phase III MYSTIC trial, a randomized, open-label, multicenter, global trial of durvalumab (Imfinzi) monotherapy or durvalumab in combination with tremelimumab vs platinum-based standard-of-care chemotherapy in previously untreated patients with metastatic (stage IV) first-line non–small cell lung cancer (NSCLC).
Progression-Free Survival Results
The combination of durvalumab and tremelimumab did not meet the primary endpoint of improving progression-free survival compared to standard of care in patients whose tumors express programmed cell death ligand 1 (PD-L1) on 25% or more of their cancer cells (as determined by the VENTANA PD-L1 (SP263) assay).
As a secondary endpoint, although not formally tested, durvalumab monotherapy would not have met a prespecified threshold of progression-free survival benefit over standard of care in this disease setting.
The trial will continue to assess two additional primary endpoints of overall survival for durvalumab monotherapy and overall survival for the durvalumab plus tremelimumab combination. Final overall survival data from both primary endpoints are expected during the first half of 2018.
Sean Bohen, Executive Vice President, Global Medicines Development and Chief Medical Officer at AstraZeneca, said, “While the results from the MYSTIC trial for progression-free survival in first-line stage IV non–small cell lung cancer compared with standard of care are disappointing, the trial was designed to assess overall survival and we look forward to evaluating the remaining primary endpoints of overall survival for both mono[therapy] and combination therapy.”